The Rausings: A gilded dynasty's troubled fortune

The arrest of Hans Kristian Rausing and the discovery of his wife's body last week threw a spotlight on a reclusive family – a clan that has engaged in vast philanthropy and yet has also struggled with the burden of extraordinary wealth

The year that Hans Kristian Rausing was born – 1963 – his grandfather Ruben Rausing launched the product that made the family rich. The Swedish entrepreneur's Tetra Brik carton was fast embraced by manufacturers around the world, transforming how we store liquids. By 1970, Ruben's company, Tetra Pak, was making more than 10bn cartons a year, and before Hans Kristian and his older sisters, Lisbet and Sigrid, were even in their teens, the Rausings were worth many, many millions.

All three have long been based in the UK, treading disparate and sometimes difficult routes through a life of unusual wealth. Lisbet and Sigrid, now in their 50s, are philanthropists and academics: Lisbet a cultural benefactor and historian of science, Sigrid the founder of a charity devoted to human rights and the figurehead of two publishers, Granta and Portobello Books.

Hans Kristian – no less cultured or inquisitive than his sisters, according to those who know him – dropped no equivalent anchors, however. The 49-year-old has suffered from drug addiction for decades, and last week his arrest on suspicion of drug possession set in motion a sequence of events that made chilling, global headlines.

When police searched his west London home after his arrest, they found the body of his wife, Eva. The exact circumstances of her death are still mysterious.

Hans Kristian and Eva, who met in a rehab clinic around 1990, had been in trouble with the police before. In June 2008, his car was seen being driven erratically after a crash in London. Reports at the time suggested he'd evaded investigating officers at the family home in Belgravia by leaping from an upstairs window. Earlier in 2008, the couple had been bailed after wraps of class-A drugs were found in Eva's handbag as she was entering a party at the US embassy; a subsequent police search of their home unearthed 50g of cocaine.

"I hope in due course I get back on track to become the person I truly want to be," said Eva in the aftermath. It does not seem she got the chance. She was 48 when she died.

Like Lisbet and Sigrid, the couple were philanthropically minded, known supporters of organisations set up to combat substance addiction. "I don't think it's a contradiction that they were supporting anti-drug charities," says an acquaintance, close to Hans Kristian in the 1990s, who spoke to the Observer on the condition of anonymity.

Hans Kristian never set up his own fund or foundation. "You can see that the sisters have been much more effective in the use of their money," said the acquaintance.

"Maybe Hans wasn't in a condition, or a position, to do similarly. From what I know of them the whole family is very public-minded, socially conscious."

It is not something the siblings have discussed much in public. Sigrid has been the most forthcoming about learning to cope with dizzying, unearned sums. "Be active with it," she once said of her philosophy about money. "It's a responsibility and it's no good avoiding that responsibility… It is only when you give it away… that money transforms from figures on a piece of paper to something in the world."

When Ruben died in 1983, his sons Gad and Hans (the youngest, and the father of Lisbet, Sigrid and Hans Kristian) jointly inherited the family business. By this time, Hans had left Sweden, moving to the UK with his wife, Marit, and the three children. The move was "to avoid punitive Swedish taxes", according to Forbes, and it proved permanent.

Hans senior settled in East Sussex, where he still lives. Sigrid went to boarding school in Oxford and then studied history at York University. Married to the South African-born film producer Eric Abraham, she has lived ever since in London and in Sussex, with a further estate in Scotland. She and Abraham have a son.

Lisbet went to university in America, studying at Berkeley and Harvard. She stayed on at Harvard to teach, and married a colleague, the art historian Joseph Koerner, with whom she had two children. She later married Peter Baldwin, a history professor, and with him founded Arcadia, a grant-giving fund established to protect cultural items and endangered species.

Neither sister appears to relish the attention-gathering side of their philanthropy. Sigrid has been willing to slow-grow a public profile, in part to encourage philanthropy in others. She has said she finds interviews "vulgar" but has been tempted to do so to encourage more giving among the wealthy in the UK. "People give a lot of money to art projects here. I think it would be a very good thing if similar kinds of sums can go into refuges for women and refugee causes."

Sigrid had set up her first charitable body in 1988, the Sea Foundation; its funds were transferred to the Ruben and Elisabeth Rausing Trust in the mid-Nineties.

Sigrid, for her own part, has spoken of a time in her youth when she was "paranoid" and "ashamed" of her wealth. This was especially the case before the family arrived in the UK from "very progressive" Sweden. "Not a good place to be a capitalist. I spent so many of my teenage years skulking in doorways, hiding away." The Rausings all have this tendency – in some cases for good reason. In the late Sixties, Gad received death threats, and in the Eighties a group of Middle Eastern terrorists were prosecuted over a plot to kidnap his son Jörn. They were planning to ransom him for $25m, and he has kept a low profile ever since.

In 1995, Gad bought his younger brother's share in the Tetra Pak packaging empire for, it is said, about $7bn. Since Gad's death in 2000, the business has been run by his widow, Birgit, and their three children.

Sigrid has admitted she sought therapy about a sense of guilt over her family wealth. "I know people who are emotionally crippled by money they inherited." Has this been the source of some of Hans Kristian's problems? Unlike his cousins, he did not go into business; nor did he embrace academia like his sisters. Instead he is said to have spent time in his youth travelling in India and Kathmandu, there experimenting with drugs. By the 1980s, he was dependent enough to seek treatment. Reports say he first met Eva Kemeny, American-born and the daughter of a wealthy businessman, in rehab. They married and settled in London. "When they were romancing and got married they were certainly both clean," says the old acquaintance. "I don't know at what point the drugs kicked back in."

They were "always very hospitable, and courteous", he recalls. "Keen to be good hosts. You know how all those British aristos who become drug addicts want to be rock stars? Hans isn't like that. He collects incredible Renaissance art and religious triptychs from the 16th century. When I knew him he was into Patti Smith, Bob Dylan, not nihilistic in any sense. There was no 'I hate my mum, I hate my dad, I'm going to rebel against everything I've been given'."

Since the discovery of Eva's body, photographs of the couple (some of uncertain date) have been published and analysed for signs of the approaching crisis. Certainly, they had appeared dishevelled, undernourished. Tabloid coverage has been predictably unsympathetic.

"I don't think this idea of them as 'the Sid and Nancy of Belgravia' is quite correct," says the acquaintance. "They had four children together; hardly a flaky undertaking. Clearly they were still struggling to get clean."

Back in 2004, giving a rare insight into this reserved family, Sigrid said of her younger self: "I found it very difficult to say no." She meant: being asked to donate money. For Hans Kristian, there was a different dictate, one also difficult to refuse.